1. Field
Various embodiments disclosed herein relate to a motion-capturing input device, with applications in virtual reality and robot control. Certain embodiments relate to a hand-motion capturing device using a mechanical approach and capable of offering force feedback.
2. Description of Related Art
There are currently a number of hand-motion capturing solutions. Some existing solutions use camera and computer vision technologies to analyze the shape and direction of a hand. Three hand-motion-capturing approaches use optical capturing, IMU (inertia measurement unit) capturing and bending sensor capturing.
Among devices that use the optical capturing approach, a device called the “Leap Motion Controller” (from Leap Motion, Inc.) uses an infrared camera to track motion of hands and utilizes algorithms to fuse data from the camera. However, some disadvantages are commonly seen in devices that use computer vision to track the motion of the hand. The ability of these devices to track hand motion is restricted due to the camera's limited monitoring scope and direction. These devices are not capable of generating a correct hand model when a user's hand is out of the camera's monitoring scope. Furthermore, an optical-capturing-based solution is unable to offer force feedback without incorporating an additional wearable device.
Another device called the “Control VR” (from Control VR) uses IMU to measure the offset angle of each finger. A disadvantage of the IMU device is the need to recalibrate the zero-offset each time the device is powered on. Additionally, because this approach involves installing drivers on the back of the user's hand, implementing force feedback is more difficult. Moreover, this approach uses bending sensors (such as a strain gauge) installed on a glove to capture hand motion. However, this approach is not able to accurately provide measurements because of the non-linear relationship between sensor readings and bending of finger. As well, it is difficult to implement force-feedback with this approach due to similar reasons as with the IMU approach. Bending sensors based approach, similar to the IMU approach, is unable to offer exact coordinates to describe finger positions due to their principles of measurements.
Furthermore, a company called CyberGlove Systems LLC offers a product called “CyberGlove”, which is a bending-sensor-based hand-motion-capturing glove with force-feedback function. The force feedback unit of the glove system is implemented using a set of steel wires and block-and-tackle systems. An external controller box is also needed for the force-feedback unit. The whole hand-motion-capturing and force-feedback system is large in volume and heavy in weight. As such, it is not portable and able to be worn easily on the hand.